breeder reactor(redirected from Breeder ratio)
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breeder reactor:see nuclear reactornuclear reactor,
device for producing controlled release of nuclear energy. Reactors can be used for research or for power production. A research reactor is designed to produce various beams of radiation for experimental application; the heat produced is a waste product and is
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a nuclear reactor in which an initial quantity of nuclear fuel is consumed and then reproduced in a greater quantity as a fissile nuclear fuel. As a rule, both the fuel consumed and the fuel produced in the reactor are made up of the same chemical element, either plutonium or uranium. Fuel is produced as a result of the interaction of the neutrons released in the fission of the initial fuel with the nuclei of a substance known as the fuel blanket (source material), which is placed in the reactor. In uranium-plutonium fast-breeder reactors 239Pu serves as the initial fuel, and 238U as the fuel blanket. The fissile material produced, 239Pu, is formed through the capture of free neutrons by the uranium nuclei. In uranium-thorium fast or slow breeder reactors, 233U serves as the initial fuel, and 232Th as the fuel blanket; 233U is the fuel produced. The doubling time, the time in which the mass of the produced fuel becomes twice as great as the beginning mass of the initial fuel, is an important quantity characterizing the operation of a breeder reactor.
The only natural nuclear fuel is 235U, and it constitutes in the natural mixture of uranium isotopes only 0.71 percent. Breeder reactors thus markedly increase the fuel base of the nuclear power industry by employing substances that cannot themselves sustain a fission reaction. Therefore, in the industrially developed countries, great attention is devoted to the problem of constructing reliable and economical breeder reactors. In the USSR, such work was started in 1949 under the direction of A. I. Leipunskii. After the construction of a series of experimental breeder reactors, the first large breeder reactor in the world, the BN-350, went into operation in 1973 at a 150-megawatt nuclear power plant in the city of Shevchenko in the Kazakh SSR. A BN-600 breeder reactor, designed for use in a 600-megawatt plant, is currently under construction.
S. A. SKVORTSOV